Vehicle control system, specific object determination device, specific object determination method, and non-transitory storage medium storing specific object determination program

ABSTRACT

A vehicle control system includes: an anti-collision safety control unit executing anti-collision safety control for avoiding or alleviating a collision with an object including a reflection point on the basis of positional information about the reflection point, output from a positional information output unit; and a cancellation unit calculating an index value that increases with a duration of a state where a variation in a position of the reflection point in a direction perpendicular to a vehicle travelling direction is smaller than a predetermined amount and that, when the index value exceeds a threshold, issues a command such that the anti-collision safety control unit does not execute anti-collision safety control over the reflection point. When it is determined that the vehicle is travelling near a curve entrance, the cancellation unit increases the threshold as compared with when it is determined that the vehicle is not travelling near a curve entrance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a vehicle control system that executesanti-collision safety control on the basis of an output from anin-vehicle radar device, and a specific object determination device, aspecific object determination method and a non-transitory storage mediumthat stores a specific object determination program, which are used inthe vehicle control system.

2. Description of Related Art

There has been practically used a technique for anti-collision safetycontrol through which a positional relationship between a vehicle and anobstacle is recognized on the basis of an output from a radar devicemounted on the vehicle and then brake control is automatically executedor an airbag is controlled in advance when there is a likelihood of acollision. With such a technique, by improving the accuracy ofrecognizing an obstacle, it is possible to further appropriately executeanti-collision safety control. For example, if it is possible toaccurately recognize a low-level metal object (that a vehicle is able torun over), such as a joint of a bridge, a steel plate for constructionand a lid (grating) of a ditch, it is possible to automatically limitbrake control and, as a result, to further appropriately executeanti-collision safety control.

Japanese Patent Application Publication No. 2010-261897 (JP 2010-261897A) describes a vehicle object detecting device that calculates the widthof an object on the basis of a position of a reflection point of anelectromagnetic wave, that further sets a position of a representativepoint of the object on the basis of positions of a plurality of thereflection points and that calculates a relative velocity in a hostvehicle width direction (lateral relative velocity) of the object on thebasis of a variation in the position of the reflection point orrepresentative point. In the vehicle object detecting device, when it isdetermined that the object is a stationary object and the amount ofincrease in the width of the object is larger than a predetermined valueon the basis of the detection history of the object detected atpredetermined intervals, a lateral relative velocity calculated bylateral relative velocity calculation means is corrected, thus improvingthe accuracy of the lateral relative velocity.

In addition, Japanese Patent Application Publication No. 2011-051572 (JP2011-051572 A) describes a vehicle control system that is used to avoida collision with an obstacle when no operation of a steering wheel hasbeen detected. The vehicle control system determines whether a road onwhich a vehicle is travelling is a curve having a bank with aninclination angle larger than or equal to a predetermined angle in avehicle width direction and, when the vehicle control system determinesthat the vehicle is travelling on a curve having a bank, sets thethreshold of a time to contact to suppress or prohibit control foravoiding a collision with the obstacle.

However, the device described in JP 2010-261897 A just corrects alateral relative velocity as a result of recognition of a stationaryobject and may not be able to appropriately determine whether it is asituation in which anti-collision safety control needs to be executed.

In addition, the system described in JP 2011-051572 A just executesanti-collision safety control when no operation of the steering wheelhas been detected, so a condition for suppressing anti-collision safetycontrol is limited to a curve having a bank, that is, a situation inwhich the vehicle is able to turn without steering operation. Therefore,the system is not applicable to other various travelling environments.

SUMMARY OF THE INVENTION

The invention provides a vehicle control system, specific objectdetermination device, specific object determination method and storagemedium storing a specific object determination program, which are ableto execute appropriate anti-collision safety control on the basis of theproperty of an object detected by a radar and a travelling environmentof a vehicle.

A first aspect of the invention provides a vehicle control system. Thevehicle control system includes: a radar unit that irradiates anelectromagnetic wave to an area around a vehicle and that outputsinformation about a received reflected wave; a positional informationoutput unit that outputs positional information about a reflection pointon the basis of the information about the reflected wave, output fromthe radar unit; an anti-collision safety control unit that executesanti-collision safety control for avoiding or alleviating a collisionwith an object that includes the reflection point on the basis of thepositional information about the reflection point, output from thepositional information output unit; a cancellation unit that calculatesan index value that increases with a duration of a state where avariation in a position of the reflection point in a directionperpendicular to a travelling direction of the vehicle is smaller than apredetermined amount and, when the index value exceeds a threshold,issues a command to the anti-collision safety control unit such that theanti-collision safety control unit does not execute anti-collisionsafety control over the object that includes the reflection point; and atravel route determination unit that determines whether the vehicle istravelling near an entrance of a curve, wherein when the travel routedetermination unit determines that the vehicle is travelling near anentrance of a curve, the cancellation unit increases the threshold ascompared with when the travel route determination unit determines thatthe vehicle is not travelling near an entrance of a curve.

According to the first aspect of the invention, it is possible toexecute appropriate anti-collision safety control on the basis of theproperty of an object detected by a radar and a travelling environmentof the vehicle.

In the first aspect of the invention, the vehicle control system mayfurther include a singular point determination unit that generates anintensity distribution of the reflected wave from the reflection pointon the basis of the information about the reflected wave, output fromthe radar unit, and that determines whether there is a statisticsingular point, wherein the cancellation unit may calculate the indexvalue such that the index value increases with the duration of the statewhere a variation in the position of the reflection point in thedirection perpendicular to the travelling direction of the vehicle issmaller than the predetermined amount when the determination unitdetermines that there is no statistic singular point in the intensitydistribution of the reflected wave from the reflection point and theindex value reduces when the determination unit determines that there isthe statistic singular point in the intensity distribution of thereflected wave from the reflection point.

In the first aspect of the invention, the anti-collision safety controlunit may execute a plurality of anti-collision safety controls, and thecancellation unit may use the threshold that is compatible with theplurality of anti-collision safety controls.

A second aspect of the invention provides a specific objectdetermination device. The specific object determination device includes:a radar unit that irradiates an electromagnetic wave to an area around avehicle and that outputs information about a received reflected wave; apositional information output unit that outputs positional informationabout a reflection point on the basis of the information about thereflected wave, output from the radar unit; an index value calculationunit that generates an intensity distribution of the reflected wave fromthe reflection point on the basis of the information about the reflectedwave, output from the radar unit, and that calculates an index value,which indicates a probability that the reflection point is included in aspecific object, such that the index value increases with a duration ofa state where a variation in a position of the reflection point in adirection perpendicular to a travelling direction of the vehicle issmaller than a predetermined amount and there is no statistic singularpoint in the intensity distribution and the index value reduces whenthere is the statistic singular point in the intensity distribution ofthe reflected wave from the reflection point; and a determination unitdetermines that the reflection point is included in the specific objectwhen the index value exceeds a threshold.

According to the second aspect of the invention, it is possible toaccurately determine the property of an object detected by a radar.

A third aspect of the invention provides a specific object determinationmethod that determines whether a reflection point is included in aspecific object by irradiating an electromagnetic wave to an area arounda vehicle and then analyzing information about a received reflected wavewith the use of a computer. The specific object determination methodincludes: determining whether there is a statistic singular point in anintensity distribution of the reflected wave from the reflection point;calculating an index value, which indicates a probability that thereflection point is included in the specific object, such that the indexvalue increases with a duration of a state where a variation in aposition of the reflection point in a direction perpendicular to atravelling direction of the vehicle is smaller than a predeterminedamount when there is no statistic singular point in the intensitydistribution of the reflected wave from the reflection point and theindex value reduces when there is the statistic singular point in theintensity distribution of the reflected wave from the reflection point;and, when the index value exceeds a threshold, determining that thereflection point is included in the specific object.

A fourth aspect of the invention provides a non-transitory storagemedium that stores a specific object determination program forirradiating an electromagnetic wave to an area around a vehicle and thencausing a computer to analyze information about a received reflectedwave and determine whether a reflection point is included in a specificobject. The specific object determination program includes: determiningwhether there is a statistic singular point in an intensity distributionof the reflected wave from the reflection point; calculating an indexvalue, which indicates a probability that the reflection point isincluded in the specific object, such that the index value increaseswith a duration of a state where a variation in a position of thereflection point in a direction perpendicular to a travelling directionof the vehicle is smaller than a predetermined amount when there is nostatistic singular point in the intensity distribution of the reflectedwave from the reflection point and the index value reduces when there isthe statistic singular point in the intensity distribution of thereflected wave from the reflection point; and, when the index valueexceeds a threshold, determining that the reflection point is includedin the specific object.

According to the third and fourth aspects of the invention, it ispossible to determine whether an object detected by a radar is thespecific object.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the invention will be described below withreference to the accompanying drawings, in which like numerals denotelike elements, and wherein:

FIG. 1 is an example of the system configuration of a vehicle controlsystem according to an embodiment of the invention;

FIG. 2A is a histogram that shows the intensity distribution of areflected wave from the same reflection point of a metal object on aroad in an ideal environment;

FIG. 2B is a histogram that shows the intensity distribution of areflected wave from the same reflection point of another vehicle in anideal environment;

FIG. 3 is a histogram that shows the intensity distribution of areflected wave from another vehicle in an actual environment;

FIG. 4 is a view that illustrates a travelling environment in which theintensity distribution of a reflected wave from another vehiclefluctuates;

FIG. 5 is a view that illustrates a travelling environment in which theintensity distribution of a reflected wave from another vehiclefluctuates;

FIG. 6 is a flowchart that shows the flow of processes executed by asystem ECU according to the embodiment;

FIG. 7A is a view that shows a change of the position of a reflectionpoint from a vehicle that travels ahead of a host vehicle;

FIG. 7B is a view that shows a change of the position of a reflectionpoint from a metal object on a road;

FIG. 8 is a graph that shows the probability of metal plate, calculatedby actually activating a radar device toward another vehicle and a metalobject on a road;

FIG. 9 is a view that shows a travelling situation in which a utilitypole is present at a roadside near an entrance of a curve; and

FIG. 10 is an example of the system configuration of a vehicle controlsystem according to an alternative embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the invention will be described withreference to the accompanying drawings.

A vehicle control system according to the embodiment of the inventionwill be described with reference to the drawing.

FIG. 1 is an example of the system configuration of the vehicle controlsystem 1 according to the embodiment of the invention. The vehiclecontrol system 1 includes a radar device 10, a radar electronic controlunit (ECU) 20, a yaw rate sensor 30, a vehicle speed sensor 32, anavigation system 40, a system ECU 50 and an activating device 60 asmajor components.

The radar device 10 is, for example, a millimeter-wave radar. The radardevice 10 is mounted at the front of a host vehicle on which the vehiclecontrol system 1 is mounted, and detects an obstacle present ahead ofthe host vehicle. The radar device 10 functions as a radar unit. Theradar device 10 includes a transmission antenna, a signal generatingunit, a receiving antenna, and the like. The transmission antennairradiates an electromagnetic wave forward of the vehicle. The signalgenerating unit generates a transmission signal to be supplied to thetransmission antenna. The receiving antenna receives a reflected wavethat is the electromagnetic wave reflected from an obstacle. Thetransmission antenna may be integrated with the receiving antenna. Interms of application purposes of the invention, any system may beemployed as the system of the radar device 10, and, for example, afrequency-modulated continuous-wave (FM-CW) system is employed.

The FM-CW system is a system in which a transmission signal of which thefrequency gradually increases and decreases is mixed with a receivedsignal to generate a beat signal, the frequency of the beat signal (beatfrequency) is identified for each of sections of an increasing portionat which the frequency of the transmission signal increases and adecreasing portion at which the frequency decreases, and a distance to ameasured object (obstacle) and a direction and a relative velocity ofthe measured object are measured by applying digital beam forming (DBF),or the like, on the basis of the beat frequency of the increasingportion and the beat frequency of the decreasing portion.

The radar ECU 20 is, for example, a microcomputer in which a centralprocessing unit (CPU) and a memory device, such as a read only memory(ROM) and a random access memory (RAM), are connected to each other viaa bus. The radar ECU 20 further includes an auxiliary storage device,TIO ports, a timer, a counter, and the like. The auxiliary storagedevice is, for example, a hard disk drive (HDD), a digital versatiledisk-recordable (DVD-R) drive, a compact disc-recordable (CD-R) driveand an electronically erasable and programmable read only memory(EEPROM). Programs to be executed by the CPU and data are stored in theauxiliary storage device.

The radar ECU 20 includes a position and velocity computing unit 22 anda metal plate flag computing unit 24 as functional blocks that functionas the CPU executes the programs. The position and velocity computingunit 22 performs various computations in the above-described FM-CWsystem and then calculates a position (distance and direction) of eachreflection point of an obstacle, from which an electromagnetic wave isreflected, and a relative velocity with respect to the host vehicle. Themetal plate flag computing unit changes on/off states of a metal plateflag on the basis of the intensity distribution of a reflected wave foreach reflection point. The position and velocity computing unit 22functions as a positional information output unit.

Here, the metal plate flag is a flag that indicates that the obstacle ishighly likely a low-level metal object on a road that the vehicle isable to run over, such as a joint of a bridge, a steel plate forconstruction and a lid (grating) of a ditch, which is intrinsicallydesired not to be set as a target of anti-collision safety control, andis set by writing a value indicating an on state or an off state to apredetermined area of the RAM, or the like.

FIG. 2A is a histogram that shows the intensity distribution of areflected wave from the same reflection point of a metal object on aroad in an ideal environment. FIG. 2B is a histogram that shows theintensity distribution of a reflected wave from the same reflectionpoint of another vehicle in an ideal environment. In FIG. 2A and FIG.2B, the abscissa axis represents a distance between the host vehicle andthe reflection point, and the ordinate axis represents an electric powerreceived by the receiving antenna of the radar device 10. The intensityof a reflected wave is indicated by an electric power received by thereceiving antenna of the radar device 10.

Here, the “same reflection point” means a series of reflection points ofwhich a fluctuation in position falls within a predetermined distancefrom a previous position while the radar device 10 repeatedly receives areflected wave. Hereinafter, description will be made on the assumptionof this definition.

FIG. 2A shows the intensity distribution of a reflected wave from ametal object on a road. FIG. 2B shows the intensity distribution of areflected wave from another vehicle. In this way, by analyzing theintensity distribution of a reflected wave, showing the correlationbetween a received electric power and a distance from the samereflection point, it is possible to determine to some extent whether anobstacle is a metal object on a road or another vehicle or anotherobject that becomes a target of anti-collision safety control. The metalplate flag computing unit 24, for example, sets the metal plate flag tothe off state when a null point (statistic singular point) shown in FIG.2B has been detected from the histogram that shows the intensitydistribution of a reflected wave, and sets the metal plate flag to theon state when the null point has not been detected from the histogram.More specifically, in the histogram that shows the intensitydistribution of a reflected wave, when a variance of reflectionintensities or difference between a maximum value and a minimum value ofthe reflection intensities in a certain infinitesimal distance sectionis larger than or equal to a predetermined value, it is determined thata null point has been detected; whereas, when a variance of reflectionintensities or difference between a maximum value and a minimum value ofthe reflection intensities in an infinitesimal distance section issmaller than the predetermined value over all the sections of thehistogram, it is determined that no null point has been detected.Various other methods are conceivable for statistically detecting asingular point, and it is not limited to the above-described method.

However, realistically, the intensity distribution of a reflected wavefrom another vehicle is not the one shown in FIG. 2B, and it may be theone shown in FIG. 3, which cannot be easily determined as the intensitydistribution of a reflected wave as shown in FIG. 2A. FIG. 3 is ahistogram that shows the intensity distribution of a reflected wave fromanother vehicle in an actual environment. In the histogram shown in FIG.3, it is highly likely that no null point has been detected.

Such fluctuations in the intensity distribution of a reflected wavedepend on a travelling environment in which the host vehicle issituated. FIG. 4 and FIG. 5 are views that illustrate travellingenvironments in which the intensity distribution of a reflected wavefrom another vehicle fluctuates. When further other vehicles aretravelling next to another intended vehicle as shown in FIG. 4 or when aguard rail, a side wall of a tunnel, or the like, is present laterallyto another vehicle as shown in FIG. 5, the intensity distribution of areflected wave can be close to the distribution shown in FIG. 2A due tothe influence of multipath, or the like.

Thus, in the vehicle control system 1 according to the presentembodiment, the type of obstacle is not determined by the metal plateflag only but utilized as one element of determination process(described later).

The radar ECU 20 outputs the position, relative velocity and metal plateflag of an obstacle to the system ECU 50.

The yaw rate sensor 30 detects a rotation angular velocity in thehorizontal direction of the vehicle. In addition, the vehicle speedsensor 32, for example, includes wheel speed sensors and a skid controlcomputer. The wheel speed sensors are respectively attached to wheels.The skid control computer calculates a vehicle speed by, for example,obtaining the average of these sensor output values, excluding anabnormal value. These sensor output values are output to the system ECU50 via a multiplex communication line, another in-vehicle ECU, or thelike.

The navigation system 40 includes a GPS receiver, a storage device, anda navigation computer. The storage device, such as an HDD, stores mapdata. The navigation computer identifies the position (latitude,longitude and altitude) of the host vehicle by analyzing a signal outputfrom the GPS receiver. In the case of the present embodiment, thenavigation system 40 outputs a signal that indicates whether the hostvehicle is travelling near an entrance of a curve to the system ECU 50.The phrase “near an entrance of a curve” is, for example, defined inadvance as a position that falls within the range of, for example, A [m]before to B [m] behind a node that indicates an entrance of a curvesection. The navigation system 40 functions as a travel routedetermination unit.

Note that means for determining whether the vehicle is travelling nearan entrance of a curve is not limited to the one with the use of thenavigation system 40; it may be determined by analyzing a signal outputfrom the radar device 10 or the yaw rate sensor 30.

The system ECU 50 has a similar hardware configuration to that of theradar ECU 20, and includes a collision determination unit 52, anactivation cancellation computing unit 54 and a device activationcontrol unit 56 as functional blocks that function as the CPU executesprograms.

The collision determination unit 52 determines whether there is alikelihood of collision with an obstacle by determining whether indexvalues, such as a lateral position (a deviation of the obstacle from theextension of the central axis of the host vehicle), a collision lateralposition (an intersection of a front end line of the host vehicle andthe trajectory of the obstacle) and a time to collision (TTC), acquiredfrom information about the obstacle (reflection points) output from theradar ECU 20, satisfy a collision determination condition.

The activation cancellation computing unit 54 cancels activation of theactivating device 60 as a result of the determination result made by thecollision determination unit 52 using the position, relative velocityand metal plate flag of the obstacle, input from the radar ECU 20. Thedetailed description will be made later. The activation cancellationcomputing unit 54 functions as a cancellation unit.

The device activation control unit 56 activates the activating device 60when the collision determination unit 52 determines that there is alikelihood of a collision and the activation cancellation computing unit54 does not cancel activation of the activating device 60. The deviceactivation control unit 56 functions as an anti-collision safety controlunit.

Various devices may be employed as the activating device 60. Forexample, the activating device 60 may be a speaker that outputs an alarmsound to a driver, an electronically-controlled brake device thatoutputs braking force independent of a depression amount of a brakepedal, an automatic steering system that outputs steering forceindependent of steering operation, or the like. In addition, theactivating device 60 may be an airbag system, a seatbelt pretensioner, abonnet activating device, or the like, for protecting a passenger, anoutside pedestrian, or the like, in the event of a collision. Inaddition, a plurality of activating devices may be provided.

Hereinafter, the flow of processes executed by the system ECU 50 will bedescribed. FIG. 6 is a flowchart that shows the flow of processesexecuted by the system ECU 50 according to the present embodiment. Theroutine is executed for each obstacle (each reflection point, and thesame applies to the following description).

First, the collision determination unit 52 determines whether thecollision determination condition is satisfied for an obstacle (S100).When the collision determination condition is satisfied, the collisiondetermination unit 52 sets a collision determination flag to an on state(S102).

Subsequently, the activation cancellation computing unit 54 determineswhether the intended obstacle is a stationary object (S104).Determination in this step is made by, for example, determining whethera change of the absolute position of the obstacle, output from the radarECU 20, is smaller than a predetermined value. Note that, for anobstacle that has been determined as not a stationary object once, itmay be determined as not a stationary object even when the obstacle isstopped thereafter (for example, when a travelling vehicle is stopped).

When the intended obstacle is a stationary object, the activationcancellation computing unit 54 extracts the probability a of metal platefor the obstacle, calculated in advance (S106).

The probability a of metal plate is a value that is repeatedlycalculated for each obstacle, in addition to the flow of the routine.The probability a of metal plate is calculated as described belowseparately in the case where the metal plate flag is in the on state andin the case where the metal plate flag is in the off state.

(1) When the metal plate flag is in the on state and when the lateralpositional deviation of the obstacle in a last predetermined period (forexample, about several hundreds of milliseconds) is smaller than apredetermined value (for example, smaller than about several tens ofcentimeters), the probability a of metal plate is increased by apredetermined value (for example, about several percent). Here, thelateral positional deviation is a variation in a direction perpendicularto the travelling direction of the host vehicle.

(2) When the metal plate flag is in the on state and the lateralpositional deviation of the obstacle in the last predetermined period isnot smaller than the predetermined value, the probability a of metalplate remains unchanged.

(3) When the metal plate flag is in the off state, the probability α ofmetal plate is reduced by a predetermined value (for example, aboutseveral percent).

In this way, the probability α of metal plate is an index value thattends to increase with the duration of a variation of the obstacle inthe direction perpendicular to the travelling direction of the hostvehicle is smaller than a predetermined amount. When the probability aof metal plate exceeds a threshold, there is a high probability that theobstacle is the above-described metal object on a road. The activationcancellation computing unit 54 functions as both an index valuecalculation unit and a determination unit.

FIG. 7A is a view that shows a change of the position of a reflectionpoint from a vehicle that travels ahead of the host vehicle. FIG. 7B isa view that shows a change of the position of a reflection point from ametal object on a road. As shown in FIG. 7A, the reflection point from avehicle that travels ahead of the host vehicle tends to wobble in thewidth direction of the host vehicle; whereas, as shown in FIG. 7B, thereflection point from a metal object on a road has small fluctuations inthe width direction of the host vehicle because an electromagnetic waveis highly likely to be reflected from one point concentratively. Thus,the probability α of metal plate is an effective index value thatindicates a probability that an obstacle is a metal object on a road.

In addition, FIG. 8 is a graph that shows the probability a of metalplate, calculated by actually activating the radar device toward anothervehicle and a metal object on a road. In FIG. 8, the abscissa axisrepresents a distance to another vehicle or metal object on a road, andthe ordinate axis represents the probability α of metal plate. As shownin the graph, the probability a of metal plate is higher than athreshold (80% in the graph) for a metal object on a road, and theprobability α of metal plate is lower than the threshold for anothervehicle.

Referring back to the flowchart of FIG. 6, the process will bedescribed. When the probability α of metal plate is extracted in S106,the activation cancellation computing unit 54 determines whether thehost vehicle is travelling near an entrance of a curve on the basis ofthe signal input from the navigation system 40 (S108).

When the host vehicle is travelling near an entrance of a curve, it isdetermined whether the probability a of metal plate exceeds a thresholdα1 (S110). When the probability α of metal plate exceeds the thresholdα1, the collision determination flag is changed to the off state (S114).

On the other hand, when the host vehicle is not travelling near anentrance of a curve, it is determined whether the probability a of metalplate exceeds a threshold α2 (S112). When the probability α of metalplate exceeds α2, the collision determination flag is changed to the offstate (S114).

Through the processes of S110 to S114, it is possible to suppressactivation of the activating device 60 for a metal object on a road,which intrinsically does not require anti-collision safety control.

Here, the relationship that the threshold α1 is larger than thethreshold α2 holds (for example, α1=90%, α2=60%, or the like). That is,when the host vehicle is travelling near an entrance of a curve, theactivation cancellation computing unit 54 does not change the collisiondetermination flag to the off state even when the probability α of metalplate is high to some extent (between the threshold α1 and the thresholdα2).

As a result, near an entrance of a curve at which the necessity ofanti-collision safety control is high, it is possible to furtheractively activate the activating device 60 for a utility pole, a pole, aguard rail, or the like, present at a roadside. FIG. 9 is a view thatshows a travelling situation in which a utility pole is present at aroadside near an entrance of a curve. A utility pole, a pole, a guardrail, and the like, exhibit a similar reflection characteristic to ametal object on a road, so the metal plate flag is highly likely to beset. Thus, it is highly likely that the calculated probability α ofmetal plate is high. However, these objects do not allow the vehicle torun over, and should be set as objects intended for anti-collisionsafety control. Then, in the vehicle control system 1 according to thepresent embodiment, a threshold used in determination made by theactivation cancellation computing unit 54 is set to be high near anentrance of a curve, and, by so doing, does not change the collisiondetermination flag to the off state even when the probability α of metalplate is high to some extent. Thus, the vehicle control system 1according to the present embodiment is able to increase the possibilitythat the activating device 60 is activated in a situation shown in FIG.9.

The thresholds α1 and α2 may be separately set in accordance with thetype of the activating device 60 (alarm sound output, automatic braking,or the like) or control system.

Note that, when the collision determination condition is not satisfiedin S100, the collision determination flag is set to the off state.

When the processes of S100 to S116 have been completed, it is determinedwhether the collision determination flag is set to the on state (S118).

When the collision determination flag is set to the on state, the deviceactivation control unit 56 activates the activating device 60 (S120).

With the above-described vehicle control system 1 according to thepresent embodiment, it is possible to execute appropriate anti-collisionsafety control on the basis of the property of an object (obstacle)detected by the radar device 10 and a travelling environment of the hostvehicle.

The embodiment of the invention is described above; however, theinvention is not limited to the above-described embodiment. Variousmodifications and replacements may be added without departing from thescope of the invention.

For example, as shown in FIG. 10, the function of the radar ECU 20 maybe one function (a radar computing unit 51 that includes a positionalvelocity computing unit and a metal plate flag computing unit) of anintegrated ECU 500. FIG. 10 is an example of the system configuration ofa vehicle control system 100 according to an alternative embodiment ofthe invention. In this way, for the arrangement of the functional unitson the hardware, various modifications are applicable.

The invention claimed is:
 1. A vehicle control system comprising: aradar unit that irradiates an electromagnetic wave to an area around avehicle and that outputs information about a received reflected wave; apositional information output unit that outputs positional informationabout a reflection point on the basis of the information about thereflected wave, output from the radar unit; an anti-collision safetycontrol unit that executes anti-collision safety control for avoiding oralleviating a collision with an object that includes the reflectionpoint on the basis of the positional information about the reflectionpoint, output from the positional information output unit; acancellation unit that calculates an index value that increases when avariation, over a predetermined period, in a position of the reflectionpoint in a direction perpendicular to a travelling direction of thevehicle is smaller than a predetermined amount and, when the index valueexceeds a threshold, issues a command to the anti-collision safetycontrol unit such that the anti-collision safety control unit does notexecute anti-collision safety control over the object that includes thereflection point; and a travel route determination unit that determineswhether the vehicle is travelling near an entrance of a curve, whereinwhen the travel route determination unit determines that the vehicle istravelling near an entrance of a curve, the cancellation unit increasesthe threshold as compared with when the travel route determination unitdetermines that the vehicle is not travelling near an entrance of acurve.
 2. The vehicle control system according to claim 1, furthercomprising: a singular point determination unit that generates anintensity distribution of the reflected wave from the reflection pointon the basis of the information about the reflected wave, output fromthe radar unit, and that determines whether there is a statisticsingular point, wherein the cancellation unit calculates the index valuesuch that the index value increases with the duration of the state wherea variation in the position of the reflection point in the directionperpendicular to the travelling direction of the vehicle is smaller thanthe predetermined amount when the determination unit determines thatthere is no statistic singular point in the intensity distribution ofthe reflected wave from the reflection point and the index value reduceswhen the determination unit determines that there is the statisticsingular point in the intensity distribution of the reflected wave fromthe reflection point.
 3. The vehicle control system according to claim1, wherein the anti-collision safety control unit executes a pluralityof anti-collision safety controls, and the cancellation unit uses thethreshold that is separately set in accordance with the anti-collisionsafety control.